Manifold imaging method and member employing fundamental particles of alpha metal-free phthalocyanine

ABSTRACT

A method of imaging wherein an electrically photosensitive imaging layer comprises electrically photosensitive fundamental alpha metal-free phthalocyanine particles greater than 1 micron in size. The imaging layer is placed between two members and imagewise exposed to an electric field and electromagnetic radiation to which the electrically photosensitive particles are sensitive. Upon separation of the members exposed particles of the layer are independently removed from the layer in imagewise configuration thereby forming a copy of the original image on one of the sheets. Production of polychromatic and monochromatic images is enhanced by control of the fundamental particle size.

United States Patent [191 Luebbe, Jr.

' Dec. 17, 1974 MANIFOLD IMAGING METHOD AND MEMBER EMPLOYING FUNDAMENTAL PARTICLES OF ALPHA METAL-FREE PHTHALOCYANINE [75] Inventor: Ray Henry Luebbe, Jr., Rochester,

[73] Assignee: Xerox Corporation, Stamford,

Conn.

[22] Filed: Feb. 1, 1972 211 App]. No.: 222,622

Related U.S. Application Data [63] Continuation-impart of Ser. Nos. 846,262, July 30, 1969, and Ser. No. 222,619, Feb. 1, 1972,

Clark 3,384,566 5/1968 96/1 PE 3,397,086 8/1968 Bartfai 96/1.5 X 3,511,651 5/1970 Rosenberg 96/1 PE 3,520,681 7/1970 Goffe 96/1 PS 3,556,781 1/1971 Levy et al.... 96/1 PS 3,556,783 1/1971 Kyriakakis 96/1.3 X 3,615,558 10/1971 Carreira et a1 96/1.3 X 3,640,710 2/1972 Mammino et a1 96/l.5 3,648,607 3/1972 Gundlach 96/1 X 3,672,979 6/1972 Gerace et a1. 96/1.5 X 3,723,113 3/1973 Goffe 96/1.2 3,767,392 10/1973 Ota 96/1 R Primary Examiner-David Klein Assistant Examiner.1ohn R. Miller 5 7] ABSTRACT A method of imaging wherein an electrically photosensitive imaging layer comprises electrically photosensitive fundamental alpha metal-free phthalocyanine particles greater than 1 micron in size. The imaging layer is placed between two members and imagewise exposed to an electric field and electromagnetic radiation to which the electrically photosensitive particles are sensitive. Upon separation of the members exposed particles of the layer are independently removed from the layer in imagewise configuration thereby forming a copy of the original image on one of the sheets. Production of polychromatic and monochromatic images is enhanced by control of the fundamental particle size.

36 Claims, 5 Drawing Figures PATENTmLcmm mmmnfz 3 $10M c YIcKMmKcXY MANIFOLD IMAGING METHOD AND MEMBER EMPLOYING FUNDAMENTAL PARTICLES OF ALPHA METAL-FREE PHTHALOCYANINE CROSS-REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of my copending US. application, Ser. No. 846,262 filed July 30, 1969 and a continuation-in-part of my copending US. application Ser. no. 222,619, filed Feb. l, 1972, now abandoned.

BACKGROUND OF THE INVENTION This invention relates in general to imaging and more specifically, to novel monochromatic and polychromatic imaging of electrically photosensitive fundamental alpha metal-free phthalocyanine particles greater than 1 micron in size.

In a typical embodiment of the monochromatic manifold imaging system, an imagable member is prepared by coating a layer of a cohesively weak photoresponsive imaging material onto a substrate. This coated substrate is called the donor. In preparation for the imaging operation, the imaging layer is activated, as by treating it with a swelling agent or partial solvent for the material. This step may be eliminated, of course, if the layer retains sufficient residual solvent after having been coated on the substrate from a solution or paste. The activating step provides the dual function of making the top surface of the imaging layer slightly tacky and, at the same time, weakening it structurally so that it can be fractured more easily along a sharp line which defines the image to be reproduced. Once the imaging layer is activated, a receiving sheet is laid down over its surface. An electrical potential is then applied across this manifold set while it is exposed to a pattern oflightand-shadow representative of the image to be reproduced. Upon separation of the donor substrate and receiving sheet, the imaging layer fractures along the lines defined by the pattern of light-and-shadow to which it has been exposed, with part of this layer being transferred to the receiving sheet while the remainder is retained on the donor sheet. Thus, a positive image is produced on one while a negative is produced on the other.

The system is capable of producing monochromatic images of excellent density and resolution. If an attempt is made to uniformly mix pigment particles responding to different colors throughout the imaging material, in some embodiments color reproduction may not be entirely satisfactory since particles of different colors scattered throughout the thickness of the imaging layer may tend to mask each other and prevent striping of single colors only in desired single colored areas.

To achieve color separation in a manifold imaging system, US. Pat. No.'3,556,783, based on the subtractive color system, provides a manifold imaging set in which the imaging material is coated onto the donor substrate as a plurality of small contiguous areas, different areas having at least two different colors which respond to lights of different colors whereby the manifold set will respond to color originals selectively so as to produce a full-color image corresponding to the original. More specifically, the plurality of small contiguous areas is provided by suitable printing methods such as gravure roller, spraying through stencils, and by conventional color lithography. As an example of the latter, three half-tone screens may be prepared, one for each of the colored patterns so that when each plate is inked with a different color, patterns will be printed on the substrate in registration. Other printing techniques typical of those found in the photolithography art may also be used. One step is that the contiguous areas of different colors be coated onto the donor substrate in registration; i.e., the different colored contiguous areas should be side by side and not super-imposed. The preparation of alpha phthalocyanine by previously known techniques, such as those disclosed in Phthalocyanine Compounds by Moser and Thomas, Rheinhold Publishing Company, pages lO4l 89, generate crystals of submicron size. In using these submicron sized particles for monochromatic imaging clean background may be difficult to achieve and in using them for polychromatic imaging they tend to adhere to one another and to any relatively larger particles.

One of the patent cases, my copending US. application Ser. No. 222,619, filed Feb. 1, 1972, provides a polychromatic imaging system using an imaging monolayer comprising pigments or dyes.

It has now been discovered that the relatively large alpha metal-free phthalocyanine particles disclosed in my copending US. application Ser. No. 846,262 can be advantageously utilized in electrically photosensitive imaging layers and monolayers sandwiched between donor and receiver members and imaged by exposure to electromagnetic radiation in the presence of an electric field.

SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide an imaging system overcoming the above-noted deficiencies.

It is another object of this invention, to provide an imaging system capable of producing Cyan colored images of cleaner background.

It is a further object of this invention to provide a clean background image comprising alpha metal-free phthalocyanine particles.

It is yet another object of this invention to provide a polychromatic imaging system utilizing an imaging mono-layer-comprising a random mixture of individual electrically photosensitive fundamental particles wherein each individual particle is of sufficiently large size to provide improved color separation and colored image density, wherein some of said particles comprise alpha metal-free phthalocyanine particles.

The above noted objects are accomplished by providing an imaging layer sandwiched between a donor member and a receiver member, wherein the layer comprises a plurality of randomly mixed particles of alpha metal-free phthalocyanine greater than 1 micron in size, having spectral sensitivity to electromagnetic radiation and responding in an electric field to radiation within said sensitivity by selective adhesion to at least one of said donor and receiver members upon sandwich separation whereby individual exposed particles are removed from the imaging layer independently of other pigment or dye particles.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows schematically, a side sectional view of a first embodiment photosensitive polychromatic imaging member for use in the invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS This invention will be primarily described with reference to its polychromatic embodiments. Monochromatic imaging with alpha metal-free phthalocyanine may be accomplished by using only the appropriate Cyan unimix instead of the two or more differently colored unimixes in the polychromatic imaging monolayer. It will be understood, of course, that the monochromatic embodiment need not necessarily employ a mono-layer but may be greater in thickness.

FIG. 1 shows a color imaging member generally designated 1 which is made up of several components. Donor member 2 has coated on one surface thereof a layer of imaging material comprising a randomly mixed mono-layer of a plurality of at least two different electrically photosensitive particle-binder agglomerates. Utilizing subtractive polychromatic image formation, these agglomerates are colored Magenta, Yellow and Cyan. The different colors for the agglomerates in FIG. 1 are indicated by M for Magenta; Y" for Yellow," and C" for Cyan.

Each particle-binder agglomerate within layer 3 of FIG. 1 contains a single color. Satisfactory particle size for the fundamental particles within the agglomerates is from I to 25 microns, optimum size is from 3 to 15 microns and the preferred size is from 5 to microns. The photosensitive particles may be transparent and provided with color suitable for use in the substractive color system. The fundamental particles have substantially the same size, and are preferably within 5 microns in size of one another.

Improved color separation in the imaging member 1 of FIG. 1 and improved color image density is insured by size control of the differently colored electrically photosensitive particles in the agglomerates of the imaging layer and the configuration of the layer such that the agglomerates may freely respond to the combined effect of electromagnetic radiation and an applied potential by selectively adhering to either of the donor or receiver members, 2 and 5, respectively, of FIG. 1, de pending upon the polarity of the applied potential. The mono-layer configuration is a random mixture of the differently colored particle-binder agglomerates so that good color balance is achieved; and more importantly, the thickness of the imaging layer is about that of the diameter of the agglomerates but no greater than twice the diameters. As can be seen from the drawings, the tops and bottoms of the agglomerates are not necessarily co-planar one with the other nor are the agglomerates necessarily touching or spaced a pre-selected distance apart. The imaging layer is, therefore, a monolayer of agglomerates and will be referred to throughout as such; but it is understood, of course, that such terminology means any configuration of agglomerates less than two complete and superimposed layer of agglomerates and one which will allow color separation of the agglomerates in the imaging method employed.

Returning now to FIG. 1, mono-layer 3, as mentioned above, comprises agglomerates comprising differently colored particles: for example, the Magenta pigment, the Yellow pigment, and the Cyan pigment are prepared to the desired particle size in separate batches (uni-mixes), the latter by the process disclosed in my copending application, U.S. Ser. No. 846,262 filed on July 30, 1969, and the former two by ball milling, and then all three uni-mixes are mixed and uniformly dispersed by sonification. Satisfactory dispersing by sonification is provided by any of the standard dispersing equipment models available from the Branson Sonic Power Company of Danbury, Conn. The uniformly dispersed particles are then coated onto the donor member 2 at a thickness equal to about the diameter of the agglomerates by any suitable coating method well known to those skilled in the art. Typical coating methods include extrusion, air-knife, reverse rod and draw down. As coated, the imaging layer comprises a randomly mixed mono-layer of a plurality of agglomerates comprising different fundamental electrically photosensitive particles. As used throughout, the term fundamental particles shall include both hard, grainlike pigment or dyes and soft, chain-forming dyes or pigments. Preferably such particles are sufficiently integral to survive the imaging process of the invention without loss of particle integrity. Fundamental particle is synonymous with individual particle," and particle entity.

Unless otherwise clearly intended, the terms agglomerates and particle-binder agglomerates" refer to the combination of fundamental particle and binder.

As shown in FIG. 1, donor member 2 has a conductive backing 4 which is optional where donor member 2 is insulating and which may be eliminated. Receiver member 5 is in contact with the upper surface of the imaging mono-layer (3) and when receiver member 5 is insulating you can optionally have, as shown in FIG. 1, a conductive backing layer 6.

To produce a full colored image with an imaging member prepared for imaging in accordance with this invention, the set is exposed to a full-color original, as by projection, through one of the members 2 and 5 with greater color fidelity and electrical photosensitivity being achieved by exposing through member 2. FIG. 3 schematically shows this exposure of the manifold to different areas of light being projected through donor substrate 2. Area 9 represents the projection of white light, area 10, the projection of no light; area 11 the projection of red light, area 12, the projection of blue light; area 13, the projection of green light; and area 14 the projection of yellow light. During the exposure of the imaging mono-layer 3 to variously colored light, an electric field is imposed across imaging material 3 between electrodes formed by conductive layers 4 and 6 of potential source 15. The polarity of the potential imposed on the donor member 2 may be either positive or negative with a preferred polarity orientation for some materials. Preferred applied potential area in the range of about 500 to about 5,000 volts per mil across the imaging member. Illustratively, were 2-mil Mylar sheets for both donor member 2 and receiver member 5 to be used, the preferred applied voltage is about 2,000 to about 20,000 volts. The potential may be imposed either before or after the receiver member 5 is brought into contact with imaging mono-layer 3. Where potentials imposed before assembly of the imaging member 1 is desirable, a resistor 16 having a resistance on the order of l to megohms is included in the circuit. This resistor prevents air gap breakdown between the imaging mono-layer 3 and receiver member 5 as they are brought together .or separated. In imaging, after exposure, the imaging member 1 is separated as shown in FIG. 4, producing a visible multicolored image. With subtractive color formation, as shown in FIG. 4, the positive image conforming to the original is ordinarily formed on the donor member 2. The applied potential is maintained across the imaging material during the separating step.

As shown in FIG. 4, white light projection in area 9 results in the transfer of the Magenta, Yellow, and Cyan colored individual agglomerates exposed to such projection to the receiver member 5, leaving a white or transparent area on donor member 2. Where no light strikes the imaging mono-layer as in area 10, all of the individual agglomerates remain on the donor substrate, combining to form a black-appearing area on donor substrate 2 via light scattering. Where red light is projected as in area 11, any Cyan material exposed will transfer to receiving sheet 5 upon strip-out leaving behind the magenta and Yellow areas which by lightscattering effect combine to appear red to the eye. Where blue light strikes the imaging material, as in area 12, the Yellow material transfer, leaving behind magenta and Cyan which combine by light scattering effect to appear blue to the eye. Where green light strikes the imaging material, as in area 13, the magenta material transfers leaving behind Yellow and Cyan which combine to appear green to the eye. Where Yellow light strikes the imaging material, as in area 14, the Magenta and Cyan materials transfer leaving behind only yellow. Integrating this phenomena over the entire surface of the donor member 2 results in a faithful fullcolor reproduction of the color original.

The embodiment of the invention depicted in FIGS. 1, 3 and 4 may have incorporated many various materials for each of the components of the manifold set.

When conductive backings 4 or 6 are used, they may be rigid, or flexible and may comprise any suitable conductive material. Typical conductive materials include: metals such as aluminum, brass, steel, copper, nickel, zinc, etc., metallic coatings on plastic substrates, rubber made conductive by the inclusion of a suitable material therein, or paper made conductive by the inclusion of a suitable material therein or through conditioning in a humid atmosphere to insure the presence therein of sufficient water content to render the material conductive.

At least one of donor member 2 or receiver member 5 should be at least partially transparent so that an image may be projected onto the imaging layer therethrough. Preferably, complete transparency is had as, for example, by use of Mylar polyester film manufactured by the Dupont Co. of Wilmington, Del. Insulating materials suitable for use in members 2 and 5 are polyethylene, polystyrene, polyethylene terephalate (Mylar polyester film), cellulose acetate, and the like, optionally backed by conductive electrode material such as evaporated tin oxide. Opaque material, such as paper, may also be used for one of these members. Either of members 2 and 5 may also singularly provide the dual characteristics of transparency and conductivity. Typical conductive transparent materials include cellophane, conductively coated glass, such as tin or indium oxide coated glass, aluminum coated glass or similar coatings on plastic substrates. NESA, a tin oxide coated glass available from Pittsburgh Plate Glass Co., is often used because it is a good conductor and is highly transparent and is readily available.

The imaging mono-layer 3 of individual agglomerates comprising fundamental particles may comprise funda mental particles of any suitable electrically photosensitive material within or on the surface of the particle agglomerates which has suitable color and spectral response. Typical highly colored photosensitive materials include: Algol Yellow GC, 1, 2, 5, 6-di (C.C'-diphenyl) thiazole-anthraquinone, C.I., No. 67300, available from General Dye Stuffs: Calcium Litho Red the calcium lake of l-(2-azonaphthalene-l sulfonic acid)-2- naphthol, C]. No. 15630 available from Collway Colors; Cyan Blue GTNF, the beta form of copper phthalocyanine, C.I. No. 74160, available from Collway Colors; Diana Blue, 3,3'-methoxy-4,4-diphenyl-bis (l "azohydroxy-3"-naphthanilide, C]. No. 21180 available from Harmon Colors; Duol Carmine, the calcium lake of 1-(4'-methylazobenzene)-2'-sulfonic acid)-2- hydroxy-Snaphthoic acid, available from E. l. du Pont de Nemours & Co.; Indofast Brilliant Scarlet Toner 3,4,9,10-bis [N.N(p-methoxyphenyl)-imidol perylene]. C.I. No. 71140, available from Harmond Colors: Indofast Yellow Toner, falvathorn C.I. No. 70600, available from Harmon Colors; Methyl Violet, a phosphotungstomolybdie lake of 4-(N.N', N"- trimethylanilino)methylene-N"N"-dimethylanilinium chloride, C.I. No. 42535, available from Collway Colors; Monolite Fast Blue GS, a mixture of the alpha and beta forms of metal-free phthalocyanine, available from the Arnold Hoffman Company; Napthol Red B, 1(2'-methoxy-5'-nitrophenylazo)-2-hydroxy-3"-nitro- 3-naphthanilide, C.l. No. 12355, available from Collway Colors; Quindo Magenta RV-6803, a substituted quinacridone, available from l-Iarmon Colors, Vulcan Fast Red BBE Toner 35-2201,3.3'-dimethoxy-4.4- biphenyl-bis( l "phenyl-3"-methl-4-azo-2- pyrozolin-5one), C.l. No. 21200, available from Collway Colors; Watchung Red B, l-(4-methyl-5- chloroazobenzene-Z-sulfonic acid)-2-hydroxy-3- naphtholic acid, C.I. No. 15865, available from E]. du Pont de Nemours & Company; and pigments prepared as described in U.S. Pat. Nos. 3,448,029; 3,448,028; 3,447,922; 3,445,277; and in U.S. Pat. No. 3,402,177. Typical photosensitive materials which may have a suitable dye incorporated to produce the desired color include 2.5-bis(p-aminophenyl)1,3,4-oxadiazol; 4,5- diphenylimidazolindine; N-isopropyl carbazole, triphenylamine; triphenylprrol; 1,4 dicyano naphthalene: 1.2.5 .6-tetraazacyclooctatctrene-( 2,4,6,8 2-phenyl)- 4-alphanaphthylidencoxazolone; 6-hydroxy-2,3-di(pmethoxyphenyl)benzofurance; 5 benxilidene-aminoaccnaphthene; 3-aminocarbazole and mixtures thereof. Any of the photosensitive materials described above may be sensitized, if desired, with suitable dye sensitizing agents or Lewis acids. Typical Lewis acids include 2,3,7-trinitro-9-fluorenone; 2,3,5,7-tetranitro-9- fluorenone; picric acid; 1,3,5-trinitro benzene and chloranil.

A suitable binder for the particle-binder agglomerates will preferably comprise insulating waxes or polymers. Typical waxes and polymers include low melt waxes such as octadecane, nonadecane, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacosane, and mixtures thereof; microcrystalline waxes such as: Sunoco 1290, Sunoco 5825, Sunoco 985, all available from Sun Oil Co.; paraflint RG, available from the Moore and Munger Company; paraffin waxes such as: Sunoco 55l2, Sunoco 3425, available from Sun Oil Co.; Sohio Parowax available from Standard Oil of Ohio; waxes made from hydrogenated oils such as Capitol City 1380 wax, available from Capitol City Products, Co. Columbus, Ohio; Caster Wax L- 2790, available from Baker Caster Oil Co.; Vitikote L-304, available from Duro Commodities; polyethylenes such as: Eastman Epolene N-ll, Eastman Epolene C-I2, available from Eastman Chemical Products, Co.; Polyethylene DYJT, Polyethylene DYLT, Polyethylene DYDT, all available from Union Carbide Corp; Marlex TR 822, Marlex 1478, available from Phillips Petroleum Co.; Epolene C-l3, Epolene C-l0,

- available from Eastman Chemical Products, Co.; Polyethylene AC8, Polyethylene AC6I2, Polyethylene AC324, available from Allied Chemicals; modified styrenes such as: Piccotex 75, Piccotex I00, Piccotex 120, available from Pennsylvania Industrial Chemical; Vinylacetate-ethylene copolymers such as: Elvax Resin 210, Elvax Resin 310, Elvax Resin 420, available from E. I. Dupont de Nemours & Co., Inc.; Vistanex MI-l, Vistanex L80, available from Enjay Chemical Co.; Vinyl chloride-vinyl acetate copolymers such as: Vinylite VYLF, available from Union Carbide Corp.; styrenevinyl toluene copolymers; polypropylenes; and mixtures thereof. The use of an electrically insulating binder is preferred because it allows the use of a larger range of electric field strengths.

The electrical potential is shown in FIG. 3 and 4 as being applied from a potential source having a conductive pathway between conductive backing 6 and conductive backing 4; that is, imaging member I is placed between electrodes (conductive backings 4 and 6) having different electrical potential. Alternatively, an electrical charge can be imposed upon one or both of the donor-member and receiving member before or after forming the sandwich by any one of the several known methods for inducing a static electrical charge into a material. Static charges can be imposed by contacting the sheet or substrate with an electrically charged electrode. Additionally, one or both sheets may be charged using corona discharge devices such as those described in U.S. Pat. No. 2,588,699 to Carlson,

U.S. Pat. No. 2,777,957 to Walkup, U.S. Pat. No. 2,885,556 to Gundlach or by using conductive rollers as described in U.S. Pat. No. 2,980,830 to Tregay et al., or by frictional means as described in US. Pat. No. 2,297,691 to Carlson or other suitable apparatus. Imaging occurs when charges are imposed. The maximum limit of applied potential is the breakdown of imaging member 1 such that conductivity of the member 1 is sufficient to prevent imaging. This will vary depending upon the materials utilized. Whether potential is applied or charges imposed, the requirement is to create an electric field across imaging mono-layer 3; for it is the combined effect of an electric field and electromagnetic radiation upon the electrically photosensitive particles which cause the particles to selectively adhere to either of members 2 and 5 upon separation of imaging member 1.

Additionally, under certain conditions, it is preferable to pre-fabricate imaging member 1 of FIGS. 1, 3 and 4. This is especially true from the viewpoint of a mere user of imaging member 1. Thus the manufacturer may wish to stabilize imaging mono-layer 3 and to render the entire imaging member 1 sufficiently rigid to withstand handling, transportation and storage operations. This can be accomplished by cementing the agglomerates within imaging layer 3 together with a soluble inter-agglomerate cement. The cement is preferably insulating.

One method of dissolving the inter-agglomerate cement (not shown) is illustrated in FIG. 2. When it is desirable to dissolve the inter-agglomerate cement of mono-layer 3, receiver member 5 is removed from the surface of imaging mono-layer 3. A solvent is applied to the surface of imaging mono-layer 3 and receiver member 5 is replaced. A spray means 7 is shown in FIG. 2 for applying solvent 8 to the exposed surface of imaging mono-layer 3. Alternatively, the solvent 8 may be applied by any suitable technique, such as with a brush, with a smooth or rough surface roller, by flowcoating, by vapor condensation or the like. After solvent 8 has been applied, the imaging member 1 is closed by roller 9 which also acts to squeeze out excess solvent.

Preferably, the particles and particle-binder agglomerates withstand the cementing and solvent addition without losing their identity or integrity as fundamental particles and particle-binder agglomerates, respectively. Although some particle disintegration is tolerable, cleaner background is produced when the particles retain their integrity in the solvent used to dissolve the cement.

Suitable cements include Piccotex 75, Piccotex I00 and Piccotex available from the Pennsylvania Industrial Chemical Co., the AROCLOR series of polychlorinated polyphenyls available from Monsanto, and other solid or semi-solid resins and polymers soluble in hydrocarbon solvents. Typical materials which are solvents, include kerosene, carbon tetrachloride, petroleum ether, silicone oils, such as dimethylpolysiloxanes, long chain aliphatic hydrocarbon oils such as those ordinarily used as transformer oils, tri chloroethylene, chlorobenzene, benzene, toluene, xylene, hexane, acetone, vegetable oils and mixtures thereof; members of the FREON series of chlorinated, fluorinated hydrocarbons available from 13.1. du Pont de Nemours; and, of preference, is Sohio Odorless Solvent 3440, a kerosene fraction available from Standard Oil of Ohio.

Referring now to FIG. 5 there is shown therein an alternative embodiment of my invention. This alternate embodiment is in all other respects identical to that in FIG. 1, 3 and 4 and like-numbered components in FIG. 5 are identical to like-numbered components in those figures. The one aspect in which these embodiments of the invention differ is the use of two adhesive layers, 17 and 18 in FIG. 5, to balance the adhesion between the mono-layer 3 and receiver member 5 with the adhesion between mono-layer 3 and donor-substrate 2. This embodiment of the invention dampens out any natural tendencies that the various suitable electrically photosensitive materials may have to possess greater adhesion for donor member 2 over receiver member 6. Adhesive layer 17 and 18 preferably comprise the same material so as to insure adhesive balance. However, layer 17 and 18 may each comprise a different material provided the adhsion is substantially balanced. For a detailed list of typical materials suitable for use in layers 17 and 18, reference is made to copending US. application Ser. No. 105,387 now U.S. Pat. No. 3,741,762 filed on Jan. 11, 1971, which is hereby incorporated by reference, and to US. Pat. No. 3,598,581, which is hereby incorporated by reference.

The materials that may be suitably incorporated within the layers 17 and 18 comprise solids and semisolids and thereby facilitate commercial manufacture, assembly, storage, maintenance and handling of the fabricated imaging member and provide a neater imaging member with which the consumer may work. The user of the imaging member fabricated in accordance with this alternate embodiment of the invention need not remove receiver sheet 5 prior to image production.

The inclusion of the layer 17 and 18 in this embodiment of the invention insures that the electrical photosensitivity phenomena of the individual fundamental particles alone determines whether the agglomerates transfer to the receiving sheet upon stripout. Suitable materials for layer 17 and 18 in FIG. 5 comprise any thermally liquifiable material having a high melt viscosity and the capability to retain electrically insulating properties to a high degree for at least a brief period of time while under high electric fields and temperatures employed in the imaging process of the second embodiment. Thermoplastic is used herein in a broad sense to indicate materials which can be affected by temperature to reduce their viscosity. Such temperatures can be of a wide range. For example, materials having a softening point as low as 5C may be suitably employed as well as materials having a softening point up to the thermodegradation temperature of the other members of the imaging member. Additionally, the resinous layer 17 and 18 can possess a wide range of viscosity in the liquid state from as low as a few poises to as high as several hundred poises at the time of image formation. Typical satisfactory materials include: low molecular weight polystyrenes such as those available commercially from the Pennsylvania Industrial Chemical Co. under the trade name Piccolastic, Series A,D,E, and F. Higher average molecular weight polystyrenes are useful and are preferably plasticized to reduce their melting point, such as Piccotex 75 Piccotex I and Piccotex 120 available also from the Pennsylvania Industrial Chemical Company.

In operation, the FIG. embodiment of the invention is practiced in all other respects in a manner identical to the practice to the first embodiment of the invention, with the added requirement that the layer 17 and 18 must be in a liquid state at the time of strip-out. That is to say, at some point of the practice of the FIG. 5 embodiment of the invention, the imaging member is subjected to a temperature which will liquify the thermally liquifiable layer 17 and 18. Such liquification can occur either before, during or after the exposure step. For some materials, normal ambient temperatures will be adequate, however, when higher melting point layers are employed, heat is applied to the manifold set.

The following examples illustrate various preferred embodiments of the present invention with respect to the formation and use of imaging members comprising fundamental particles of electrically photosensitive alpha metal-free phthalocyanine greater than 1 micron in size. All values are to be read as being prefaced by the word about.

EXAMPLE I A Cyan uni-mix is made as follows:

a. A 15 percent alcoholic KOH solution is prepared by dissolving 30 gms. of Reagent grade KOH pellets into 170 ml. of absolute ethanol while stirring in a glass jar. The jar is tightly closed and thereby shielded from air during dissolution. After dissolution the clear liquid is decanted and slurried with 30 gms. of Monolite Fast Blue B.X. (a commercial grade of metal-free alphaphthalocyanine available from Arnold Hoffman Company) and allowedto stand for 13 days, again under airtight seal. The slurry is then filtered through a medium porosity sintered glass funnel, re-slurried twice in diionized water, filtered again, re-slurried twice in diionized water, re-slurried with 0.1 N NHqOH, filtered again, re-slurried twice more with di-ionized water, reslurried twice with Reagent grade Methanol, filtered again and dried overnight in a drying oven at C. Three grams of the dried material is added to 60 ml. of clay column purified DC Naphtha (available from Dow Corning); the combination is subjected to anultra-sonic field twice for 30 seconds with an intervening 2 minute delay between submissions.

b. A polymer dispersion is prepared by adding 0.3 gms. of polyethylene DYLT (Union Carbide), 1.5 gms. paraflint -RG (Moore-Munger), 0.5 gms. of Elvax 420 (Du Font), and 2.5 gms. of Piccotex 75 (Pennsylvania Industrial Chemical Co.) to 20 ml. of SOHIO 3440 (clay column purified) available from Standard Oil of Ohio. The combination is heated until dissolved and then cooled to room temperature.

c. The polymer dispersion resulting in (b) is added to the sonified combination resulting in (a), sonified for 30 seconds, heated and held at C for 2 hrs., cooled to room temperature, added to 60 ml Reagent-grade iso-propyl alcohol and sonified for 30 seconds. The resultant is a Cyan unimix of particle-binder agglomerates from about 15 to 25 microns in size comprising fundamental particles of metal free alphaphthalocyanine from about 15 to 20 microns in size.

A monochromatic Cyan imaging member is prepared by coating the uni-mix on a 4X6 inch rectangle of 1 mil Mylar with a No. 26 Meyer wire-wound rod. and drying the coated Mylar (donor) for 3 minutes at 43C. The coated Mylar is then placed Mylar side down on the tin oxide surface ofa NESA glass plate. A 4X6 inch rectangle of 2 mil polystyrene (Dow Chemical), the receiver member, is moistened with one quick brush stroke of a camels hair brush saturated with SOHIO Ordorless Solvent 3440 and positioned on the coated Mylar with its moistened surface in contact with the coating, thereby forming the imaging member. A roller is rolled along the free surface of the polystyrene receiver member to squeeze out excess SOHIO. An electric potential of IO KV is applied between the tin oxide NESA surface and the polystyrene free surface. The imaging member is exposed through the coated Mylar to 2 foot- EXAMPLE ll The procedure of Example I is followed except as follows: A second uni-mix which is Yellow in color is prepared by adding 3 gms. of the yellow pigment described in U.S. Pat. No. 3,447,922 (N-2"-pyridyl-8, l3 dioxodinaphtho (2,l6; 2'; 3-d)-furan-6-carboxamide to 60 cc of DC Naptha (clay column purified) and ball milled for 1.75 hours at 60 rpm using /a inch to 4 inch diameter flint stones. A polymer dispersion is made as in (b) of example I and is added and the combination is ball milled for 2 hrs heated and maintained at 65C for 2 hours, cooled to room temperature, and added to 60 ml. of Reagent grade iso-propyl alcohol. Ball milling is continued for 20 minutes, resulting in a Yellow unimix of particle-binder agglomerates to 25 microns in size)) comprising fundamental particles of Yellow pigment (15 to microns in size). The Yellow and Cyan uni-mixes are combined in a 2:1 ratio, respectively, and this mixture is used to coat and prepare the imaging member following the imaging procedure of Example I. The NESA glass is heated to 45C during imaging. Exposure is through a target comprising yellow, cyan, green, and clear filter areas. Upon separation of the imaging member, the receiver bears positive, slightly grainy, yellow, cyan, green and clear images in areas corresponding to the filters in the test target.

EXAMPLE Ill The procedure of Example ll is followed except as follows: the polymer dispersion disclosed in (b) of Example l is made without the inclusion of polyethylene DYLT and instead of being mixed with the pigments in preparing the uni-mixes the heated polymer dispersion coated upon the Mylar donor member with a No. 12 Meyerjwire-wound rod, cooled and air-dried prior to coating with the mixture of cyan and yellow uni-mixes. Each of the uni-mixes are prepared without the inclusion of the polymer dispersion in (b) of Example I and without the heating and cooling cycle of (c) of Example I. The resulting donor member comprises a Mylar substrate, a coating of polymer dispersion on the donor member and a mono-layer of randomly mixed cyan and yellow colored fundamental particles of electrically photosensitive material residing on the polymer dispersion coating. The SOHIO moistened polystyrene receiver member is placed atop the mono-layer of fundamental particles and pressed down with the hand roller. The mono-layer is depressed into the polymer dispersion and becomes a mono-layer of particle-binder agglomerates.

EXAMPLE IV The procedure of Example ll is repeated except as followsithe slurry of Monolite Fast Blue 6.8. and alcoholic KOH is allowed to stand for only 5 days but is otherwise prepared and treated as in (a) of Example I; the yellow pigment is prepared as in Example ll except that it is initially ball milled for 14 hours. Each resulting unimix comprised particle-binder agglomerates of from about 7 to 12 microns in size which comprise fundamental pigment particles of from about 5 to ID microns in size. The resulting image is grainless and has very little background.

EXAMPLE V A color imaging member is prepared and imaged as in Example II with the following modifications: The polymer dispersion (b) and heat treatment (c) of Example l is dispensed with in preparing the unimixes. Prior to coating and assembly of the imaging member, adhesive layers are made on the donor and receiver members with a No. 12 Meyer draw-down rod from a suspension of a mixture of about 2.5 parts eicosane (technical grade, a mixture of predominately straight chain hydrocarbons averaging 20 carbon atoms in the molecule) and about 7.5 parts Sunoco 5825, a tetroleum wax available from the Sun Oil Company, suspended in 100 parts of Sohio Odorless Solvent 3440; the suspension is coated onto the members and airdryed. Then the coated donor member is coated with the unimixes and the dry receiver member placed on top thereof. Immediately prior to separation of the receiver member the layers are melted by raising their temperature to 65C. A color image is observed on the receiver member after separation.

EXAMPLES Vl AND VII The procedure of Example V is followed except that in Example Vl the layers are melted prior to exposure and in Example Vll, during exposure.

EXAMPLE Vlll An imaging member is prepared and imaged as in Example ll with the following modifications: after the coating of agglomerates are dried on the donor member, a cement is applied to the coating by dissolving 15 grams of Piccotex in 500 ml. of petroleum ether (B.P. 60-ll0C) and then passing over the coating with one quick brush stroke of a wide camels hair brush saturated with the solution; after air drying of the ether component of the applied solution, the remaining Piccotex component is further dried by heating at 75C for 5 minutes thereby cementing the agglomerates one to the other, then the receiver member is placed over the cemented coating; prior to imaging the receiver member is removed and the cement dissolved by using a petroleum ether saturated brush as above, then the receiver member is replaced.

EXAMPLE lX An imaging member is prepared and imaged as in Example ll with the following modifications: the combined unimixes are coated directly onto the Mylar donor member and a 6 micron coating of Bioloid Paraffin Embedding Compound (M.P. 5052C), available from the Will Corporation of Rochester, N.Y., is placed on the dry polystyrene receiver member. After exposure and before separation of the imaging memher, the imaging member is heated to 55C.

EXAMPLE X An imaging member is prepared and imaged as in Example lX except that the Bioloid coating is placed on the Mylar donor member and the combined uni-mixes are coated on top of the Bioloid coating. The dry polystyrene receiver member is placed atop the combined uni-mix coating prior to imaging.

Although specific components and proportions have been stated in the above description of preferred embodiments of the invention, other typical materials as listed above, if suitable, may be used with similar results. In addition, other materials may be added to the components to synergize, enhance or otherwise modify their properties.

It is to be understood of course that various wax materials, such as those listed for the binder in the particle-binder agglomerates may be used for adhesive layers 17 and 18 and for the cementing of the mono-layer. Further, it is to be understood that the steps and materials used can be varied without departing from the spirit of this invention. For example, the donor and receiver members may be in web form suitable for machine imaging and transfer of the image by mechanical and electrical means to a suitable substrate, as, for example, disclosed in copending U.S. application Ser. No. 104,340 now U.S. pat. No. 3,248,034 filed on Jan. 6, 1971; and various treatments given the electrically photosensitive materials utilized to vary various properties thereof. Further, the cement may be applied to the uni-mixes prior to confiquring the imaging member. Also, the color of the positive image may be amplified by light buffing, as with a wad of cotton, so as to smear the colored agglomerates and thereby cover the areas on the receiver or donor member in between agglomerates.

Finally, in those embodiments where air space exists between the donor andreceiver members, an insulating material, preferably SOHIO Ordorless Solvent is applied just prior to imaging. Preferably, such insulating material does not hinder the independent removal of agglomerates upon separation. The air space is preferably filled with such insulating materials to prevent airgap discharge through the imaging member while it is under electrical potential.

It will be understood that various changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the invention will occur to those skilled in the art upon the reading of the disclosure. It may be that other substances exists or may be discovered that have some or enough of the properties of the particular materials described to be used in their place. Other modifications and ramifications of the present invention will occur to those skilled in the art upon the reading of the present disclosure. These are intended to be included within the scope of this invention.

What is claimed is:

l. A method of imaging comprising providing an imaging layer sandwiched between a donor member and a receiver member, at least one of said members being at least partially transparent to electromagnetic radiation to which said imaging layer is sensitive, said imaging layer comprising electrically photosensitive fundamental particles of alpha metal-free phthalocyanine in the range of from greater than 1 micron to about microns in size and substantially of uniform size; exposing said imaging layer to a pattern of electromagnetic radiation to which said particles are sensitive while applying an electric field across said imaging layer; and during the application of said field separating said receiver member from said donor member whereby exposed particles are removed from said imaging layer in imagewise configuration forming an image conforming to the original on at least one of said members.

2. The method of claim I wherein said fundamental particles are from about3 to 15 microns in size.

3. The method of claim 1 wherein said fundamental particles are from about 5 to 10 micronsin size.

4. A method of imaging comprising a. providing an imaging mono-layer sandwiched between a donor member and a receiver member, at least one of said members being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive, said mono-layer comprising a plurality of electrically photosensitive fundamental particles of alpha metal-free phthalocyanine in the range of from greater than 1 micron to about 25 microns in size, and substantially uniform in size, each individual particle of said plurality being removable from said mono-layer independently of the other mono-layer particles;

b. exposing said mono-layer to a pattern of electromagnetic radiation to which said particles are sensitive while applying an electric field across said imaging mono-layer; and

c. during the application of said field separating said receiver member from said donor member whereby exposed individual particles are removed from said mono-layer in imagewise configuration forming an image conforming to the original on at least one of said members.

5. The method of claim 4 wherein said fundamental particles are from about 3 to about 15 microns in size.

6. The method of claim 4 wherein said fundamental particles are from about 5 to 10 microns in size.

7. The method of claim 4 wherein at least one of said members is electrically insulating.

8. The method of claim 7 wherein said electric field is caused by the induction of a static electrical charge onto at least one of said members.

9. The method of claim 4 wherein said electric field is caused by the application of a potential.

10. The method of claim 9 wherein said potential is from about 500 volts to about 5,000 volts per mil thickness of the donor member imaging mono-layer receiver member sandwich.

11. The method of claim 4 wherein at least one of said members is a web.

12. The method of claim 11 wherein said web is the receiver member and further including the step of transferring by mechanical and electrical means and fundamental particles thereto a substrate.

13. The method of claim 4 further including the addition of an insulating, soluble inter-agglomerate cement to the mono-layer of fundamental particles.

14. The method of claim 13 wherein said cement is soluble in a hydrocarbon solvent.

15. The method of claim 14 further including the step of dissolving said cement prior to imaging by the appli cation of a hydrocarbon solvent.

16. The method of claim 4 further including the step of adding thermoplastic adhesive layers, one each inbetween said mono-layer and said members, thereby balancing the adhesion between said mono-layer and said donor member with that between said mono-layer and said receiver member.

17. The method of claim 16 further including the step of subjecting said adhesive layers to a temperature sufficient to liquify said adhesive layers.

18. The method of claim 17 wherein said adhesive layers are liquitied prior to exposure of said mono-layer to said pattern of electromagnetic radiation.

19. The method of claim 17 wherein said adhesive layers are liquified during exposure to said pattern of electromagnetic radiation.

20. The method of claim 17 wherein said adhesive layers are liquified subsequent to exposure to said pattern of electromagnetic radiation.

21. A method of color imaging comprising:

a. providing an imaging mono-layer sandwiched between a donor member and a receiver member, at least one of said members being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive said mono-layer comprising a plurality of at least two different electrically photosensitive fundamental particles, each of 20 said at least two particles having a different color and a corresponding different spectral sensitivity and said particles being substantially uniform in size, one of said two particles comprising alpha metal-free phthalocyanine in the range of from greater than I micron to about microns in size, .each individual particle of said plurality being removable from said mono-layer independently of other particles;

b. exposing said mono-layer to a pattern of electromagnetic radiation to which at least one of said two particles is sensitive while applying an electric field across said imaging mono-layer; and

c. during the application of said field separating said receiver member from said donor member whereby exposed individual particles are removed from said mono-layer in imagewise configuration forming a colored image conforming to the original on at least one of said members.

22. The method of claim 21 wherein said imaging mono-layer comprises a random mixture of different colors of said fundamental particles.

23. the method of claim 22 wherein said pattern of electromagnetic radiation comprises radiation to which all of said particles are sensitive and wherein said image on at least one of said members is a multi-colored image comprising at least two different colors.

24. An imaging member comprising a mono-layer photosensitive fundamental particles of alpha metalfree phthalocyanine in the range of greater than 1 micron to about 25 microns in size and substantially uniform in size.

25. The imaging member of claim 24 wherein said fundamental particles are from about 3 to about 15 microns in size.

26. The imaging member of claim 24 wherein said fundamental particles sizes are from about 5 to about 10 microns.

27. The imaging member of .claim 24 wherein at least one of said donor and receiver members is transparent.

28. The imaging member of claim 24 wherein at least one of said donor and receiver members is electrically insulating.

29. The imaging member of claim 24 wherein at least one of said donor and receiver members is a web.

30. The imaging member of claim 24 further comprising an insulating, soluble inter-agglomerate cement in-between said fundamental particles.

31. The imaging member of claim 24 further comprising two thermoplastic adhesive layers, one each in between said mono-layer and said donor and receiver members.

32. An imaging member comprising an imaging mono-layer comprising a plurality of at least two different electrically photosensitive fundamental particles of substantially uniform size, at least one of said at least two particles comprising alpha metal-free phthalocyanine in the range of greater than 1 micron to about 25 microns in size residing on the donor member and a receiver member residing on said particles at least one of said donor and receiver member being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive.

33. The imaging member of claim 32 wherein said imaging mono-layer comprises a random mixture of different colors of said fundamental particles.

34. The imaging method of claim 21 further including the step of amplifying said colored image by smearing the colored particles.

35. An imaged receiver member the image of which comprises alpha electrically photosensitive metal-free phthalocyanine fundamental particles in the range of from greater than 1 micron to about 25 microns in size provided by the process of claim 1.

36. An imaged donor member the image of which comprises electrically photosensitive alpha metal-free phthalocyanine fundamental particles in the range of from greater than 1 micron to about 25 microns in size provided by the process of claim 1. 

1. A METHOD OF IMAGING COMPRISING PROVIDING AN IMAGING LAYER SANDWICHED BETWEEN A A DONOR MEMBER AND A RECEIVER MEMBER, AT LEAST ONE OF SAID MEMBERS BEING AT LEAST PARTIALLY TRANSPARENT TO ELECTROMAGNETIC RADIATION TO WHICH SAID IMAGING LAYER IS SENSITIVE, SAID IMAGING LAYER COMPRISING ELECTRICALLY PHOTOSENSITIVE FUNDAMENTAL PARTICLES OF ALPHA METAL-FREE PHTHALOCYANINE IN THE RANGE OF FROM GREATER THAN 1 MICRON TO ABOUT 25 MICRONS IN SIZE AND SUBSTANTIALLY OF UNIFORM SIZE; EXPOSING SAID IMAGING LAYER TO A PATTERN OF ELECTROMAGNETIC RADIATION TO WHICH SAID PARTICLES ARE SENSITIVE WHILE APPLYING AN ELECTRIC FIELD ACROSS SAID IMAGING LAYER; AND DURING THE APPLICATION OF SAID FIELD SEPARATING SAID RECEIVER MEMBER FROM SAID DONOR MEMBER WHEREBY EXPOSED PARTICLES ARE REMOVED FROM SAID IMAGINING LAYER IN IMAGEWISE DONFIGURATION FORMING AN IMAGE CONFORMING TO THE ORIGINAL ON AT LEAST ONE OF SAID MEMBERS.
 2. The method of claim 1 wherein said fundamental particles are from about 3 to 15 microns in size.
 3. The method of claim 1 wherein said fundamental particles are from about 5 to 10 microns in size.
 4. A method of imaging comprising a. providing an imaging mono-layer sandwiched between a donor member and a receiver member, at least one of said members being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive, said mono-layer comprising a plurality of electrically photosensitive fundamental particles of alpha metal-free phthalocyanine in the range of from greater than 1 micron to about 25 microns in size, and substantially uniform in size, each individual particle of said plurality being removable from said mono-layer independently of the other mono-layer particles; b. exposing said mono-layer to a pattern of electromagnetic radiation to which said particles are sensitive while applying an electric field across said imaging mono-layer; and c. during the application of said field separating said receiver member from said donor member whereby exposed individual particles are removed from said mono-layer in imagewise configuration forming an image conforming to the original on at least one of said members.
 5. The method of claim 4 wherein said fundamental particles are from about 3 to about 15 microns in size.
 6. The method of claim 4 wherein said fundamental particles are from about 5 to 10 microns in size.
 7. The method of claim 4 wherein at least one of said members is electrically insulating.
 8. The method of claim 7 wherein said electric field is caused by the induction of a static electrical charge onto at least one of said members.
 9. The method of claim 4 wherein said electric field is caused by the application of a potential.
 10. The method of claim 9 wherein said potential is from about 500 volts to about 5,000 volts per mil thickness of the donor member - imaging mono-layer - receiver member sandwich.
 11. The method of claim 4 wherein at least one of said members is a web.
 12. The method of claim 11 wherein said web is the receiver member and further including the step of transferring by mechanical and electrical means and fundamental particles thereto a substrate.
 13. The method of claim 4 further including the addition of an insulating, soluble inter-agglomerate cement to the mono-layer of fundamental particles.
 14. The method of claim 13 wherein said cement is soluble in a hydrocarbon solvent.
 15. The method of claim 14 further including the step of dissolving said cement prior to imaging by the application of a hydrocarbon solvent.
 16. The method of claim 4 further including the step of adding thermoplastic adhesive layers, one each inbetween said mono-layer and said members, thereby balancing the adhesion between said mono-layer and said donor member with that between said mono-layer and said receiver member.
 17. The method of claim 16 further including the step of subjecting said adhesive layers to a temperature sufficient to liquify said adhesive layers.
 18. The method of claim 17 wherein said adhesive layers are liquified prior to exposure of said mono-layer to said pattern of electromagnetic radiation.
 19. The method of claim 17 wherein said adhesive layers are liquified during exposure to said pattern of electromagnetic radiation.
 20. The method of claim 17 wherein said adhesive layers are liquified subsequent to exposure to said pattern of electromagnetic radiation.
 21. A method of color imaging comprising: a. providing an imaging mono-layer sandwiched between a donor member and a receiver member, at least one of said members being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive said mono-layer comprising a plurality of at least two different electrically photosensitive fundamental particles, each of said at least two particles having a different color and a corresponding different spectral sensitivity and said particles being substaNtially uniform in size, one of said two particles comprising alpha metal-free phthalocyanine in the range of from greater than 1 micron to about 25 microns in size, each individual particle of said plurality being removable from said mono-layer independently of other particles; b. exposing said mono-layer to a pattern of electromagnetic radiation to which at least one of said two particles is sensitive while applying an electric field across said imaging mono-layer; and c. during the application of said field separating said receiver member from said donor member whereby exposed individual particles are removed from said mono-layer in imagewise configuration forming a colored image conforming to the original on at least one of said members.
 22. The method of claim 21 wherein said imaging mono-layer comprises a random mixture of different colors of said fundamental particles.
 23. the method of claim 22 wherein said pattern of electromagnetic radiation comprises radiation to which all of said particles are sensitive and wherein said image on at least one of said members is a multi-colored image comprising at least two different colors.
 24. An imaging member comprising a mono-layer sandwiched between a donor member and a receiver member, at least one of said donor and receiver members being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive said mono-layer comprising a plurality of electrically photosensitive fundamental particles of alpha metal-free phthalocyanine in the range of greater than 1 micron to about 25 microns in size and substantially uniform in size.
 25. The imaging member of claim 24 wherein said fundamental particles are from about 3 to about 15 microns in size.
 26. The imaging member of claim 24 wherein said fundamental particles sizes are from about 5 to about 10 microns.
 27. The imaging member of claim 24 wherein at least one of said donor and receiver members is transparent.
 28. The imaging member of claim 24 wherein at least one of said donor and receiver members is electrically insulating.
 29. The imaging member of claim 24 wherein at least one of said donor and receiver members is a web.
 30. The imaging member of claim 24 further comprising an insulating, soluble inter-agglomerate cement in-between said fundamental particles.
 31. The imaging member of claim 24 further comprising two thermoplastic adhesive layers, one each in between said mono-layer and said donor and receiver members.
 32. An imaging member comprising an imaging mono-layer comprising a plurality of at least two different electrically photosensitive fundamental particles of substantially uniform size, at least one of said at least two particles comprising alpha metal-free phthalocyanine in the range of greater than 1 micron to about 25 microns in size residing on the donor member and a receiver member residing on said particles at least one of said donor and receiver member being at least partially transparent to electromagnetic radiation to which said mono-layer is sensitive.
 33. The imaging member of claim 32 wherein said imaging mono-layer comprises a random mixture of different colors of said fundamental particles.
 34. The imaging method of claim 21 further including the step of amplifying said colored image by smearing the colored particles.
 35. An imaged receiver member the image of which comprises alpha electrically photosensitive metal-free phthalocyanine fundamental particles in the range of from greater than 1 micron to about 25 microns in size provided by the process of claim
 1. 36. An imaged donor member the image of which comprises electrically photosensitive alpha metal-free phthalocyanine fundamental particles in the range of from greater than 1 micron to about 25 microns in size provided by the process of claim
 1. 